1. Field
This disclosure relates to mixer circuits.
2. Description of Related Art
Mixer circuits are commonly used in a number of applications. As one example, they are often used in radio frequency (RF) applications for up-converting (up-mixing) or down-converting (down-mixing). In this context, up-converting is the process of mixing a base band signal, such as a differential base band signal, with an RF signal, such as a differential RF signal that is generated by a local oscillator circuit that operates in the RF range. This process generates a mixed RF signal with the base band information included with (mixed with) the RF signal generated by the local oscillator. Down-converting is the process of separating (un-mixing) the base band signal from the mixed RF signal. This is typically accomplished by using a mixer circuit with a local oscillator of substantially an identical frequency as was used to mix the mixed RF signal.
One typical type of mixer circuit is a passive mixer circuit, which may be implemented using a complementary-metal-oxide semiconductor circuit fabrication process (e.g. an integrated circuit). In such circuits, the operation of such mixer circuits is dependent on the linear range of those circuits. In this respect, the linear range of the circuit affects the one decibel (1 dB) compression point and the third intercept point (IP3), which are measures of the adverse affects of non-linearities on the gain and performance of such circuits. In this respect, current approaches for implementing passive mixer circuits have certain limitations. These limitations include included limited linear ranges, which result in 1 db compression points and IP3 points that are unacceptable for RF signals with higher amplitudes (e.g. these circuits have insufficient gain when processing such signals). Therefore, alternative approaches for implementing such circuits are desirable.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.